Process of tapping nut-blanks.



0'. A. SMITH.

' PROCESS OF TAPPING NUT BLANKS.

APPLICATION FILED DEO.26, 1907.

v Patented Sept. 29, 1908.

2 SHEETS-SHEET 1.

. witn esses: In Yemen w B9 6 71 w w Z 0. A. SMITH. PROCESS OF TAPPINGNUT BLANKS. APPLICATIQN III-ED DEG. 26-, 1907.

. 900 042 V Patented Sept. 29, 1908-.

' 2 sums-SHEET 2.

In Willa).-

00001145101112; fiyiziidllazm N TED STATES PATENT omnon.

OSCAR A. SMITH, or CLEVELAND, 01110, Assre von TO EDWIN o. HENN, orCLEVELAND,

' OHIO.

PROCESS 'OF T APPING NUT-BLANKS.

Specification of Letters Patent.

Patented Sept. 29, 1908.

Original applications filed August 16,1306, Serial No.. 330,894, andAugust 24, 1906, Serial No. 331,825. Divided and this application filedDecember 26, 1907. SeriaINo. 408,164.

To all whom it may concern: 7 a

Be it known that I, OSCAR A. SMITH, a at zen of the United States,residing in Cleveland, in the county of'Cuyahoga and State of Ohio, haveinvented certain new and useful Improvements in Processes of Tapping NutBlanks, of which the following is aspecification. i

This invention relates to the method of cutting'threads in the bores ofnut-blanks and other members, the object of the invention being toprovide an improved method whereby a seriesof nuts or nut blanks orother members are brought into position and while in such osition theblanks are, by means of a sing etool or cutter, automatically andsuccessively cut or tapped from oposite sides, that is to say, one nutblank will be cut or tapped fromone side, the tool passing therethrough,while a successive nut blank will becut or tapped fromthe op osite sidei by the same tool passing bac ward therethrough. 9 i p a The present aplication is a divisional aplication of that fi led by me Au ust 24,1906, erial No. 331,825, and of that ed by me on the 16th dayof August,1906, Serial No. 330,894. i

In the present method the. cutter'or tap, which is in the form of adouble ended, reversible tap, is passed entirely through the boreof thenut blank to cut a; thread therein, and then returned through thebore ofa successive blank to out the same kind of a thread therein, the nutblanksbeing identical, so that by the present method successive nutblanks are cut from op osite sideswith the same kind of threadan by. theuse'of a single tool.

The present method consists rotating and advancing a pair of opposedtoolholding means alternately to engage by its opposite ends a doubleended tool efiective to cut from either end, therebyto pass it throughblanks to cut thesame kind of thread in such blanksfirst from onejside(and then from the other of successive blanks, said tool holding meansbeing rotated together at the. same speed during the cutting of .oneblank one direction and during the cutting'of a successive blank in theopposite direction.

One embodiment of a machine adapted for carrying out the presentmethodis shown in the accompanying drawings,.in which Figure 1 shows afront elevation; Fig. 2 is an end elevatiom Fig. 3 is a detail view inelevation and section, showing one of the socketspindles for operatingthe tap; Fig. 4 is an end View of the latter spindle; Figs. 5,

6 and 7 show thetap with its operating spmdles and a magazine for thenut-blanks, the tap and spindles being in successive ositions; Fig. 8isa vertical section throug the magazine, showing its mechanism forfeedingthe nut-blanks successively; and Fig. 9

is a view of the tap.

The special form of tap that the machine is designed to operate has thecutter portion or located at the intermediate part of a shank b, theteeth being fullyformed at the middle portion of the cutter, but reducedtowards each end of the shank, instead of toward one end as in the usualconstruction. These teeth at one end are given the usual backward rakeor inclination, but the rake at one end portion is in the oppositedirection circumferentially fromlthose at the other end.

This is forthe reason that when one end of the tap is inserted, thecutting teeth adjacent that end will have the usual backward rake tocommence cutting the threads in the nut. The tap having passed entirelythrough the nut, is operated endwise in the opposite direction for thenext blank. But, obviously, the'tap must now be rotated in the oppositedirection, since the thread cut will now be the same as in the previousblank. Therefore, the direction of rotation being reversed, thedirection of the rake or inclination of: the cutting teeth adjacent thisend must be reversed.

The present machine, which is adapted for carrying out the process,comprises essentially two operating spindles that engage the oppositeends of the tap-shank respectively, and a magazine or holder, denotedgenerally by M, whereby the nut-blanks can be successively fed to acertain position, and rigidly held in such position while being engagedby .the tap. The tap is engaged by one spindle and passed into the nut,by rotating the spindle and at the same time advancing it;

in other words, giving it a spiral movement.

Upon the tap passing partly through the nutblank, as indicated in Fig.6, its emerging end is. engaged by the spindle member on the oppositeside, which, obviously must rotate at l the same speedr The threadspartially cut in the nut-blank will of themselves advance the tap,moving it into the second spindle socket. Thereupon, the first spindleupon approaching the nut, will cease its advance, While the otherspindle must retreat while rotating; that is, must move spirally awayfrom the magazine. Upon the thread por tion of the tap disengaging thenut, the second spindle will continue the advance of the tap, therebycausing it to travel entirely through the nut-blank, At this stage thetapped blank is ejected, and the succeeding blank fed to and locked inthe same position. The second spindle now has its movement arrested andreversed to travel in the opposite rotative and advancing direction;that is, is moved in an opposite spiral direction. This will carry theend that has just moved out of the last blank, first into the nextblank, .and the opposite end of the cutter portion will first engage thenut-blank to start the thread in its bore. The continued rotatingmovement of the spindle, together with the advancing motion caused bythe threads of the cutter and nut-blank, will carry the tap on throughthe second blank. Upon its entering end passing through the nut-blank itis engaged by the first spindle, that will now be given a spiralmovement corresponding to that of the operating spindle. Upon the tappassing further through the blank, the second spindle will be arrestedin its advancing movement, and the first spindle will retreat, carryingthe tap entirely through the second blank and free thereof. Thereuponthis nut-blank is ejected and the succeeding one placed in tappingposition. The cycle of operations is now repeated as described, eachsucceeding nut-blank being tapped from opposite sides, but obviously thesame identical thread is formed in each nut.

In the construction shown, on a suitable frame-work F are mountedspindles 2 and 3, one at each end of the machine, that are in alinement.These spindles are carried in one or more bearings 4 and 5 at each end,the spindles being endwise movable in the bearings as well as rotatable.Suitable means are provided whereby each spindle is rotated throughoutits range of endwise movement. In the form shown, each s )indle carriesa gear 6 meshing with an eiongated pinion 7, the gear 6 remaining inmesh therewith throughout its endwise move ment. The two pinions 7 arefast on the shaft 8, extending from end to end of the machine, anddriven by a pulley 9 fast thereon. Idle pulleys 10 and 11 are loose onthe shaft on opposite sides of the pulley 9 to which reversing belts 12and 13 are shifted, whereby the motion of the shaft 8 is reversed in theusual manner from two oppositely moving belts.

Each of the spindles is provided with means for engaging and disengagingthe tap to rotate it and at the same time advance the tap. As shown,each. spindle is provided with a socket member 14, shown separately inFigs. 3 and 4. This socket member is provided with a bore 15 fitting theshank of the tap, with reduced portions 16 on opposite sides of thesocket, engaging flat portions on the tap-shank, to prevent rotation ofthe tap in the socket. By means a of the main shaft 8 the two spindleswill be simultaneously revolved and their motion reversed. The spiralmotion. of the spindles and sockets is, in the present construction,effected by means of cam straps. A shaft 17 is rotatable on the frame,preferably at its lower part, and driven by a pulley 18 fast thereon,from a belt 19, running on any suitable counter-shaft, not shown. On theshaft 17, near one end of the machine, is secured a drum 20, providedwith cam-straps 21 and 22. A lever 23 is pivoted on the machine bed andhas a forked end 24 engaging opposite sides of a disk 25 on the spindle2. The lower end of the lever is engaged. by the cam-straps 21 and 22.These straps are so designed and located on the drum that the spindlewill first be advanced in one direction, then allowed to rotate in suchposition without advancing, .and then moved back in its former position.Near the other end of the shaft 1.7 is a similar drum 26, )1'0- videdwith strap-cams 27 and 28 that alternately engage the lower end of alever 29 pivoted on the machine bed. This lever has a forked end 30engaging a disk 31 on the sJindle 3. By this means the spindle 3 is alternately moved in opposite directions, similar to the operation of thespindle 2.

Means are provided whereby the revolution of the driving shaft 8, andhence that of the two spindles, is reversed at the proper time when thetap has passed. entirely through one blank and another is presented fortapping. This means is preferably controlled by the shaft 17 and timedrelative to the position of the cam-straps on the controlling drums. Inthe construction illustrated, a drum 32 is fast on one end of the shaft17, near the nest of pulleys operating the shaft 8. The drum is providedwith a cam groove 33 in its peri )hery, whose walls engage one end of abelt-shifter lever 34. By this means, when the cam-straps have shiftedthe spindles to one end, the beltshifter is o erated to shift thedriving belt to the idle pu ley and bring the other belt on to thedriving pulley, thereby reversing the spindles.

The nut-blanks in the construction disclosed, are fed through a magazineor tube 1O, whose here is such that the nuts can slide down through themagazine, but are prevented from rotating therein or having any movementexcept to advance. The nuts are ward movement.

retained in operative position bymeans of a lever 41 ivoted at 42 on themagazine, and having a ent arm 43 arranged to engage the two lower sidesof the nut-blank; thereby retaining the blank in positionlfor threading.The other end 44 of the'lever, upon'being rocked to cause the end 43 tomoveout of the tube and free the nut, will engage the lower side of thesucceeding nut and prevent its advancement until the first nut has beenremoved. Should this tapped nut not fall by gravity, the armf44,infmoving into position to engage the underside of a succeedingnutblank, will strike the upper or rear side of the tapped or finishednut and start its down- Upon the return movement of the lever, the arm43 is in position to arrest the downward movement of theneXt nut-blankas soon as the arm 44 releases the blank, permitting it to advance.Suitable means are provided for rocking the arm 41. It is shown ashaving a slottedarm-45 that is engaged by a slide 46 movable in a block47. The slide 46 is controlled by a cam 48 that'is operated from anyconvenient part of the machine. the lower end of the slide.

'In the operation of themachine the tap engaged by one of the spindles,as -spindle 3, is moved to the right while rotating, to'en gage thepositioned nut-blank. As the tap advances through the same, the secondspindle 2 is moved in'the opposite direction to receive the end of thetapas it passes through the blank. The spindles being constantly rotatedin the samejdirection and at the same speed, they will have thetap-engaging portions always inthe same relative position. The emergingend of the tap will therefore enter the socket of the second spindle andproperly engage its flattened portions therein. At this period theadvance ofv the first spindle will be arrested, while the second splndlewill begin to retreat. The threads started in the nut-blank will havethe effect of continuing the'endwise movement of S1136 direction intothe nut-blank.

The cam engages a roller 49 on engaged from the first spindle,thisspindle is caused to retreat to its former position. The tappedblank is now ejected and a succeeding one looked in the same position.

The straps on the operating drum now cause the second spindle toadvance, and the end of the tap that just passed out of the last blank,is moved into the now positioned blank. But

the belt-shifter has operated to reverse the driving shaft 8, and hencethe rotation of the spindles, and the tap now moves in the oppo- At thisstage .the first spindle is again caused to approach the magazine, andas soon as the tap begins to pass through the bore of the nut-blank itsend is engaged by the socket of the first spindle. The atter spindle nowbegins to retreat, and as soon as the second sequence, as at eachrotation of the operating shaft 17 the spindles must be given a completereciprocatlon.

I claim as my invention:

1. The method of cutting blanks which consists in passing a double-endedtool so constructed as to cut, when moved endwise,

in-both directions, through a blank one end foremost, and then passingit in a reverse direction through a ank with its other end foremost.

2. The method of tapping nuts, which consists in holdinga dou le endedtap by one end and screwing its other end foremost into a perforatednut. blank, taking hold of the advancing end and. screwing it entirelythrough the blank, releasing its opposite end,

thenreversing its rotation and screwing it back through end foremost.

OSCAR A. SMITH.

Witnesses:

J. H. DOHNER, E. C. HENN.

anothernut blank opposite

